The invention relates in general to the reception and processing of bioelectrical signals from an organism. Furthermore, the invention relates to an improved method and apparatus for receiving bioelectrical signals, processing the signals and signaling back to the organism so as to allow the organism to either inhibit or facilitate a selected frequency.
A number of different feedback-type methods and apparatus are known dating back to as early as 1960. Early studies by several researchers focused on bioelectrical feedback on persons suffering from hemiplegia, i.e., paralysis of one lateral half of the body resulting from injury to the motor centers of the brain.
In 1960, A. A. Marinacci and M. Horande investigated neurofeed back with respect to left-sided hemiplegia. As reported in "Electromyogram in Nueromuscular Re-education", Bulletin of the Los Angeles Neurologic Society, 25: 57-71, 1960, they inserted needle electrodes into the involved left arm muscles, and could find no voluntary nerve impulses. Electrodes were inserted into the normal right deltoid to show the patient how muscle activity could produce auditory feedback. The electrodes were then inserted into the paralyzed left deltoid muscle. The patient was able to generate from 10 to 15 percent motor action potential in a location from which there had been no previous detectable activity. The same procedure was utilized successfully at other muscle sites.
In 1964, J. M. Andrews reported on study utilizing a patient group of hemiplegics who had electromyogram EMG electrodes inserted in the involved tricep muscles as reported in "Neuromuscular Re-education of the Hemiplegic with the Aid of the Electromyograph," Archives of Physical Medicine and Rehabilitation, 45: 530-532, 1964. Auditory feedback was provided as the subjects tried to generate sound and movement. A five-minute trial period was allowed, and seventeen out of the twenty patients showed an increase in motor action potentials.
In 1973, H. E. Johnson and W. E. Garton reported on ten hemiplegic patients, who utilized EMG practices as an aid in total rehabilitation rather than just the return of voluntary movement as in the Andrews study as discussed in "Muscle Re-education in Hemiplegia by use of Electromyograph Device", Archives of Physical Medicine and Rehabilitation, 54: 320-325, 1973. Five out of ten subjects had enough improvement to eliminate leg bracing on the involved side.
In 1974, J. Brudny and others used EMG feedback to treat a group of thirty-six patients, thirteen of whom had hemiparesis. Brudny, J. Korein, J., Levidow, L. Grynbaum, B. B., Lieberman, A., and Friedman, L. W., "Sensory Feedback Therapy as a Modality of Treatment in Central Nervous Disorders of Voluntary Movement," Neurology, 24: 925-932, 1974. In this study surface electrodes were used instead of inserted needle electrodes. In two individuals there was no change. In one patient there was relief from muscle spasticity. In six patients function of the extremity was re-established, and in four cases prehension became possible.
Also, in 1974, D. Swaan, P. C. W. Van Wieringer and S. D. Fokkema explored EMG feedback of seven patients, four of whom were hemiplegic. "Auditory Electromyographic Feedback Therapy to Inhibit Undesired Motor Activity," Archives of Physical Medicine and Rehabilitation, 57:9-11, 1974. The subjects taught to inhibit the peroneus longus muscle while contracting their quadricep muscle. Conventional rehabilitation methods were used to suppress the undesirable hyperactivity of the peroneus longus muscles along with the feedback. No justification was given for reinforcement of the quadriceps and inhibition of the peroneus longus.
In 1975, J. V. Basmajian, C. G. Kukulka, M. G. Narayan and K. Takebe compared EMG biofeedback plus physical therapy with the results of standard rehabilitation procedures in cases of ankle dorsiflexion paralysis after stroke repeated in "Biofeedback Treatment of a Foot-Drop After Stroke Compared With Standard Rehabilitation Techniques: Effects on Voluntary Control and Strength," Archives of Physical Medicine and Rehabilitation, 56: 231-236, 1975. The authors claimed that an increase in both strength and range of motion in the biofeedback group was twice as great as the achievements of the exercise control group. The two groups of patients were not variably matched. When biofeedback was added to physical therapy, the mixed variables were not controlled.
In 1976, L. P. Taylor and B. Bongar described the use of electromyometry feedback for the treatment of cerebrovascular lesion patients in Clinical Applications in Biofeedback Therapy, Psychology Press, Los Angeles, Calif., 1976. Patients were taught to inhibit one set of muscles while simultaneously facilitating others. For example, inhibition of thumb flexion was attempted while thumb extension was facilitated.
In 1979, F. Keefe and K. Trombly utilized EMG feedback to aid a hemiplegic patient judge limb position without being able to see the limb in "Impaired Kinesthetic Sensation: Can EMG Feedback Help?" Presented at the Proceedings of Biofeedback Society of America, Tenth Annual Meeting, February, 1979 in San Diego, Calif. The patient participated in an A-B-A-B withdrawal design to evaluate the effects of EMG biofeedback on accurate limb positioning. EMG feedback with audio feedback produced improvement in performance relative to baseline. Withdrawal of feedback produced a decrement in performance, and when EMG feedback was re-instituted, performance once again improved. The patient was able to generalize the EMG feedback training to improved functional use of the arm.
In 1979, R. Koheil, et al, at the Ontario Crippled Children Centre, developed a Joint Position Trainer to provide precise feedback of limb position to three hemiplegics. Koheil, R., Mandel, A., Herman, A. and Iles, G., "Joint Position Training for Hyperextension of the Knee in Stroke Patients: Preliminary Results", presented at the Proceedings of the Biofeedback Society of America, Tenth Annual Meeting, February, 1979 in San Diego, Calif. The Joint Position Trainer provided feedback of position rather than of muscle activity, and incorporated a goniometer attached to a leg cuff with auditory feedback of knee joint angle. Two of the three patients developed improved gait with increased control of knee hyperextension.
The results of the techniques involved had limited results because the difficulty of recognizing particular frequencies generated which could not be readily determined, nor could the subject have the ability to control these frequencies.
Other research efforts were conducted specifically upon those bioelectrical signals emanating from the brain. One of the earlier works was written in 1966 by T. Mullholland and C. R. Evans who described the use of alpha waves (approximately 7.5-11.5 Hertz) emanating from the brain to drive a feedback signal that could be perceived by the test subject and induce relaxation. Mulholland, T., and Evans, C. R., Nature, 211: 1278, 1966. The alpha waves could be controlled to some degree by the test subject's recognition of a tone or light when alpha waves were produced. Similarly, differentiation of particular frequencies of bioelectrical signal prevented the test subject from readily acknowledging and either inhibiting or facilitating particular frequencies.
Other electroencephalograph (EEG) feedback devices are described in publications by Spunda, J. and Radil-Weiss, T., "A Simple Device for Measuring the Instaneous Frequency of the Dominant EEG Activity", Electroencephalographic Clinical Neurophysiology, 32: 434, 1972. This device converted EEG frequencies into voltage levels for analysis using bandpass analysis. A series of wave form generators were activated by the flip-flop at each positively directed zero point of the filtered signal resulting in a voltage level corresponding to the frequency.
Another EEG feedback device was described in Hicks, R. G., and Angner, E., "Instrumental evaluation of EEG Time Relationships", Psychophysiology, 6:44, 1970. This device analyzed minute time displacements of EEG waves from cortical waves using peak detection and a type of logic as a feedback device.
Also, in Boudrot, R., "An Alpha Detection and Feedback Control System", Psychophysiology, 9:467, 1972, a feedback device picked up alpha waves and provided auditory and visual stimulus feedback to the patient. Then, in Pfeifer, E. A., and Usselmann, C., "A Versatile Amplitude Analyzer for EEG Signals to Provide Feedback Stimuli to the Subject", Med. Biol. Eng. 8: 309, 1970, a feedback device analyzed the amplitude and provided feedback cues to subjects in studies of EEG modification. It allowed for usage with bandpass analysis incorporating logic components and a display.
Additionally, U.S. Pat. No. 3,837,331 to Sidney A. Ross, issued Sept. 24, 1974, entitled "System and Method for Controlling the Nervous System of a Living Organism" describes an apparatus and method for determining particular frequencies of a bioelectric signal which is analog by nature. The Ross device like the other devices require the use of band pass analysis or other techniques to filter out particular frequencies to study a particular frequency of interest.
In band pass analysis, analog filters analyze how much frequency is produced in a given period of time, or a frequency in relationship to time and voltage. The apparatus required includes a precision attenuator, an active band pass filter, a rectifying means and an integrating means in addition to those components normally utilized in bioelectrical feedback devices. Furthermore, band pass analysis or power spectral analysis is necessary to isolate the particular frequency of interest. Such analysis is typically performed on a large computer requiring special analytical skills and extensive computing time. Power spectral analysis looks at the variance of a bioelectrical signal or the covariance between one or more signal channels. The signal is broken into different frequency bands in relationship to the power density which is then analyzed using a fourier series program.
Not only is the above approach burdensome and time consuming, but also inaccurate. The frequency results are often distorted because the analytical approach used is based on exponential and logrithic analysis. Determining the actual frequency desired to inhibit or facilitate is at best haphazard due to the margins for error in the above approach.
Also, the above referenced devices lack suitable means for displaying and recording the changing frequencies under study for subsequent review and manipulation for purposes of analysis. But, most importantly, these EEG feedback devices lacked the ability to establish selected limits or thresholds in which to gauge the progress of a test subject or reward the test subject once the test subject learned to inhibit or facilitate a particular frequency of interest.
The above-mentioned deficiencies are overcome by the present invention. There is a great interest in the neuropsychology and neurophysiology community for such a device which overcomes these deficiencies. Researchers and practitioners should recognize the value immediately of the present invention. Furthermore, persons suffering from nervous disorders, induced by trauma, drug use or cogenital aberration can greatly benefit from the present invention. The present invention operates as a diagnostic tool, as well as, a means for curing nervous disorders or abnormalities in the body, particularly the brain.